2026/2027 – Midterm Comprehensive Examination with
Verified Questions and Correct Answer Rationales
Question 1: A 65-year-old male with a history of hypertension presents with a
sudden onset of severe chest pain that radiates to his back. Aortic dissection is
suspected. Which of the following pathophysiological mechanisms best
explains the propagation of the dissection?
A. Weakening of the tunica adventitia due to chronic inflammation
B. A tear in the tunica intima allowing blood to enter the tunica media
C. Rupture of the vasa vasorum leading to intramural hematoma
D. Degeneration of the tunica externa due to atherosclerotic plaque
CORRECT ANSWER: B. A tear in the tunica intima allowing blood to enter the
tunica media
Rationale: An aortic dissection typically begins with a tear in the tunica intima. This
tear allows high-pressure blood to enter the tunica media, creating a false lumen that
propagates along the aortic wall. This separates the intimal layer from the media, which
can compromise branch vessels and lead to rupture.
Question 2: A patient with chronic alcoholism presents with muscle weakness,
paresthesias, and ophthalmoplegia. Which vitamin deficiency is most likely
responsible for these neurological manifestations?
A. Vitamin B12 (Cobalamin)
B. Vitamin B6 (Pyridoxine)
C. Vitamin B3 (Niacin)
D. Vitamin B1 (Thiamine)
CORRECT ANSWER: D. Vitamin B1 (Thiamine)
Rationale: The triad of ophthalmoplegia, ataxia, and confusion (Wernicke's
encephalopathy) is caused by a thiamine (Vitamin B1) deficiency. This is common in
chronic alcoholism, which impairs thiamine absorption and utilization, leading to
impaired glucose metabolism in the brain.
Question 3: A 55-year-old female with rheumatoid arthritis develops a
normocytic, normochromic anemia. Which of the following is the most likely
underlying cause?
A. Iron deficiency from chronic blood loss
B. Vitamin B12 deficiency from gastric atrophy
C. Folate deficiency from methotrexate therapy
D. Anemia of chronic disease due to elevated hepcidin
,CORRECT ANSWER: D. Anemia of chronic disease due to elevated hepcidin
Rationale: Anemia of chronic disease (ACD) is common in autoimmune disorders like
rheumatoid arthritis. Pro-inflammatory cytokines (like IL-6) stimulate hepatic production
of hepcidin, which sequesters iron in macrophages and reduces intestinal iron
absorption, leading to a normocytic, normochromic anemia.
Question 4: A newborn is diagnosed with a congenital heart defect
characterized by a right-to-left shunt. Which of the following findings would
you expect on physical examination?
A. Bounding peripheral pulses
B. Cyanosis with a systolic ejection murmur
C. A continuous machine-like murmur
D. Wide pulse pressure
CORRECT ANSWER: B. Cyanosis with a systolic ejection murmur
Rationale: A right-to-left shunt allows deoxygenated blood to bypass the lungs and
enter systemic circulation, causing cyanosis. The systolic ejection murmur is typical of
the turbulent flow across the shunt, such as in Tetralogy of Fallot or truncus arteriosus.
Question 5: A 45-year-old male presents with jaundice, dark urine, and right
upper quadrant pain. Liver biopsy reveals a dense infiltrate of neutrophils in
the portal tracts. Which of the following is the most likely diagnosis?
A. Alcoholic hepatitis
B. Acute viral hepatitis
C. Primary biliary cholangitis
D. Autoimmune hepatitis
CORRECT ANSWER: A. Alcoholic hepatitis
Rationale: The combination of jaundice, dark urine, and RUQ pain with a neutrophilic
infiltrate on biopsy is characteristic of alcoholic hepatitis. While other forms of hepatitis
can cause similar symptoms, the presence of a pronounced neutrophil response, Mallory
bodies, and steatosis is more specific to alcoholic liver disease.
Question 6: A patient with chronic obstructive pulmonary disease (COPD) has
an arterial blood gas (ABG) showing pH 7.31, PaCO2 60 mmHg, and HCO3- 28
mEq/L. What is the primary acid-base disorder?
A. Metabolic acidosis with respiratory compensation
B. Metabolic alkalosis with respiratory compensation
,C. Acute respiratory acidosis
D. Chronic respiratory acidosis with metabolic compensation
CORRECT ANSWER: D. Chronic respiratory acidosis with metabolic
compensation
Rationale: The pH is low (acidemia) and PaCO2 is high, indicating a respiratory
acidosis. The HCO3- is also elevated (compensatory metabolic alkalosis). Since the
HCO3- elevation is greater than the 1 mEq/L increase for every 10 mmHg rise in
PaCO2 expected in an acute scenario, this signifies a chronic process with significant
renal compensation.
Question 7: A 30-year-old female presents with severe, throbbing headaches
accompanied by nausea, vomiting, and photophobia. These episodes are
preceded by a visual aura of flashing lights. Which of the following
pathophysiological mechanisms is most associated with the aura phase?
A. Vasodilation of meningeal arteries
B. Release of substance P from trigeminal nerve endings
C. Cortical spreading depression causing neuronal depolarization
D. Activation of the hypothalamus
CORRECT ANSWER: C. Cortical spreading depression causing neuronal
depolarization
Rationale: The visual aura in migraine with aura is primarily caused by cortical
spreading depression (CSD). This is a wave of neuronal depolarization followed by
prolonged suppression of brain activity that propagates across the cortex, leading to the
transient neurological symptoms of the aura.
Question 8: A patient with a history of peptic ulcer disease is prescribed an
NSAID for osteoarthritis. Which of the following is the primary mechanism by
which NSAIDs increase the risk of gastric ulcers?
A. Direct acid secretion by parietal cells
B. Inhibition of cyclooxygenase-1 (COX-1), reducing mucosal prostaglandins
C. Stimulation of the vagus nerve increasing gastric motility
D. Inhibition of cyclooxygenase-2 (COX-2), increasing leukotriene production
CORRECT ANSWER: B. Inhibition of cyclooxygenase-1 (COX-1), reducing
mucosal prostaglandins
Rationale: NSAIDs inhibit COX-1, which is constitutively expressed in the gastric
mucosa. Its inhibition leads to a decrease in cytoprotective prostaglandins that normally
maintain the mucosal barrier, reduce acid secretion, and promote blood flow, making
the stomach more susceptible to injury from gastric acid.
, Question 9: A 70-year-old male with a history of smoking and hypertension
presents with gradual memory loss and difficulty walking. MRI shows diffuse
white matter changes and lacunar infarcts. This clinical presentation is most
consistent with:
A. Alzheimer's disease
B. Lewy body dementia
C. Frontotemporal dementia
D. Vascular dementia
CORRECT ANSWER: D. Vascular dementia
Rationale: Vascular dementia is caused by cerebrovascular disease and is
characterized by a stepwise decline in cognitive function. The presence of diffuse white
matter changes (leukoaraiosis) and lacunar infarcts on MRI, along with classic risk
factors (smoking, HTN), strongly supports this diagnosis.
Question 10: A patient with a history of congestive heart failure is prescribed
furosemide. Which of the following electrolyte imbalances is a common
adverse effect of this medication that can precipitate cardiac arrhythmias?
A. Hypernatremia
B. Hyperkalemia
C. Hypomagnesemia
D. Hypercalcemia
CORRECT ANSWER: C. Hypomagnesemia
Rationale: Loop diuretics like furosemide inhibit sodium-potassium-chloride
cotransport in the thick ascending limb of the loop of Henle, leading to increased
excretion of sodium, potassium, chloride, and magnesium. Hypomagnesemia can
precipitate life-threatening cardiac arrhythmias, especially in patients on digoxin.
Question 11: In a patient with acute pancreatitis, which pathophysiological
mechanism is responsible for the hypocalcemia often observed?
A. Parathyroid hormone deficiency
B. Vitamin D deficiency
C. Saponification of calcium in necrotic fat tissues
D. Renal calcium wasting
CORRECT ANSWER: C. Saponification of calcium in necrotic fat tissues
Rationale: In acute pancreatitis, lipase released from the pancreas breaks down
peripancreatic fat into free fatty acids. These free fatty acids bind with ionized calcium